The present invention relates to a steering lock apparatus for use in vehicles and the like.
Conventionally, a cylinder lock that allows locking and unlocking without a key has been disclosed in e.g., Japanese Utility Model Kokoku Publication No. 61-28851. This cylinder lock has a rotor equipped with plate-shaped tumblers, and a rotational cylinder with tumbler engagement grooves formed on an inner circumferential face is provided on an outer circumference of the rotor. In the rotational cylinder, there is provided a hole for fitting a top end portion of a plunger driven by an electromagnetic solenoid. When the electromagnetic solenoid is off, the plunger is fit into the hole to prevent rotation of the rotational cylinder, whereas when the electromagnetic solenoid is on, the plunger leaves the hole to bring the rotational cylinder into a rotatable state. For unlocking the cylinder lock with use of a key, the key is inserted into the rotor so that the tumblers sink into the rotor, which releases engagement between the tumblers and the grooves of the rotational cylinder, and thereby enables the rotor to rotate in precisely the same way as general cylinder locks. For unlocking the cylinder lock without use of a key, the electromagnetic solenoid is operated to pull the plunger out of the hole of the rotational cylinder so as to make the rotational cylinder rotatable. In this state, holding and rotating a knob provided on a front face of the rotor implements cooperative rotation of the rotor and the rotational cylinder since the tumblers of the rotor are in engagement with the tumbler engagement grooves of the rotational cylinder.
Generally in steering lock apparatuses, when a key is inserted and a cylinder is rotated from LOCK position to ACC position with use of the key, a steering shaft is unlocked, and this unlocking state is maintained in ON position, Start position, ACC position, and LOCK position after once unlocking the steering shaft. Then, the steering shaft is locked when the key is extracted from the key cylinder in LOCK position. However, in the known steering lock apparatus, since key extraction cannot be detected, operating the key or the knob to the LOCK position after unlocking the steering shaft causes a lock shaft spring out, and thereby locks the steering shaft.